Buggy code:
private Text dragConsole ; private boolean dragEventDetail = false ; private Text dropConsole ; private boolean dropEventDetail = false ; private static final int BUTTON_TOGGLE = 0 ; private static final int BUTTON_RADIO = 1 ; private static final int BUTTON_CHECK = 2 ; private static final int CANVAS = 3 ; private static final int LABEL = 4 ; private static final int LIST = 5 ; private static final int TABLE = 6 ; private static final int TREE = 7 ; private static final int TEXT = 8 ; public static void main ( String [ ] args ) { } private void addDragTransfer ( Transfer transfer ) { } private void addDropTransfer ( Transfer transfer ) { } private void createDragOperations ( Composite parent ) { } private void createDragSource ( ) { } private void createDragTypes ( Composite parent ) { } private void createDragWidget ( Composite parent ) { } private void createDropOperations ( Composite parent ) { } private void createDropTarget ( ) { } private void createFeedbackTypes ( Group parent ) { } private void createDropTypes ( Composite parent ) { } private void createDropWidget ( Composite parent ) { } private Control createWidget ( int type , Composite parent , String prefix ) { switch ( type ) { case DNDExample . BUTTON_CHECK : { Button button = new Button ( parent , SWT . CHECK ) ; button . setText ( ( prefix + "<seq2seq4repair_space>Check<seq2seq4repair_space>box" ) ) ; return button ; } case DNDExample . BUTTON_TOGGLE : { Button button = new Button ( parent , SWT . TOGGLE ) ; button . setText ( ( prefix + "<seq2seq4repair_space>Toggle<seq2seq4repair_space>button" ) ) ; return button ; } case DNDExample . BUTTON_RADIO : { Button button = new Button ( parent , SWT . RADIO ) ; button . setText ( ( prefix + "<seq2seq4repair_space>Radio<seq2seq4repair_space>button" ) ) ; return button ; } case DNDExample . TABLE : { Table table = new Table ( parent , ( ( SWT . BORDER ) | ( SWT . MULTI ) ) ) ; table . setHeaderVisible ( true ) ; TableColumn column0 = new TableColumn ( table , SWT . LEFT ) ; column0 . setText ( "Name" ) ; TableColumn column1 = new TableColumn ( table , SWT . RIGHT ) ; column1 . setText ( "Value" ) ; TableColumn column2 = new TableColumn ( table , SWT . CENTER ) ; column2 . setText ( "Description" ) ; for ( int i = 0 ; i < 10 ; i ++ ) { TableItem item = new TableItem ( table , SWT . NONE ) ; item . setText ( 0 , ( ( prefix + "<seq2seq4repair_space>name<seq2seq4repair_space>" ) + i ) ) ; item . setText ( 1 , ( ( prefix + "<seq2seq4repair_space>value<seq2seq4repair_space>" ) + i ) ) ; item . setText ( 2 , ( ( prefix + "<seq2seq4repair_space>description<seq2seq4repair_space>" ) + i ) ) ; } column0 . pack ( ) ; column1 . pack ( ) ; column2 . pack ( ) ; return table ; } case DNDExample . TEXT : { Text text = new Text ( parent , ( ( ( ( SWT . BORDER ) | ( SWT . MULTI ) ) | ( SWT . V_SCROLL ) ) | ( SWT . H_SCROLL ) ) ) ; text . setText ( ( prefix + "<seq2seq4repair_space>Text" ) ) ; return text ; } case DNDExample . TREE : { <START_BUG> Tree tree = new Tree ( parent , SWT . BORDER ) ; <END_BUG> tree . setHeaderVisible ( true ) ; TreeColumn column0 = new TreeColumn ( tree , SWT . LEFT ) ; column0 . setText ( "Name" ) ; TreeColumn column1 = new TreeColumn ( tree , SWT . RIGHT ) ; column1 . setText ( "Value" ) ; TreeColumn column2 = new TreeColumn ( tree , SWT . CENTER ) ; column2 . setText ( "Description" ) ; for ( int i = 0 ; i < 3 ; i ++ ) { TreeItem item = new TreeItem ( tree , SWT . NONE ) ; item . setText ( 0 , ( ( prefix + "<seq2seq4repair_space>name<seq2seq4repair_space>" ) + i ) ) ; item . setText ( 1 , ( ( prefix + "<seq2seq4repair_space>value<seq2seq4repair_space>" ) + i ) ) ; item . setText ( 2 , ( ( prefix + "<seq2seq4repair_space>description<seq2seq4repair_space>" ) + i ) ) ; for ( int j = 0 ; j < 3 ; j ++ ) { TreeItem subItem = new TreeItem ( item , SWT . NONE ) ; subItem . setText ( 0 , ( ( ( ( prefix + "<seq2seq4repair_space>name<seq2seq4repair_space>" ) + i ) + "<seq2seq4repair_space>" ) + j ) ) ; subItem . setText ( 1 , ( ( ( ( prefix + "<seq2seq4repair_space>value<seq2seq4repair_space>" ) + i ) + "<seq2seq4repair_space>" ) + j ) ) ; subItem . setText ( 2 , ( ( ( ( prefix + "<seq2seq4repair_space>description<seq2seq4repair_space>" ) + i ) + "<seq2seq4repair_space>" ) + j ) ) ; for ( int k = 0 ; k < 3 ; k ++ ) { TreeItem subsubItem = new TreeItem ( subItem , SWT . NONE ) ; subsubItem . setText ( 0 , ( ( ( ( ( ( prefix + "<seq2seq4repair_space>name<seq2seq4repair_space>" ) + i ) + "<seq2seq4repair_space>" ) + j ) + "<seq2seq4repair_space>" ) + k ) ) ; subsubItem . setText ( 1 , ( ( ( ( ( ( prefix + "<seq2seq4repair_space>value<seq2seq4repair_space>" ) + i ) + "<seq2seq4repair_space>" ) + j ) + "<seq2seq4repair_space>" ) + k ) ) ; subsubItem . setText ( 2 , ( ( ( ( ( ( prefix + "<seq2seq4repair_space>description<seq2seq4repair_space>" ) + i ) + "<seq2seq4repair_space>" ) + j ) + "<seq2seq4repair_space>" ) + k ) ) ; } } } column0 . pack ( ) ; column1 . pack ( ) ; column2 . pack ( ) ;

Fix:
Tree tree = new Tree ( parent , ( ( SWT . BORDER ) | ( SWT . MULTI ) ) ) ;